I had to go make sure I watched the same game as others. I did not find Sarr dreadful in defense. That said, he would get punished in the PL. He is undersized and does not anticipate the ball well so he does not get ahead of the attack and is defending moving back all the time.
Malang Sarr [45] - 6/10
Fired an effort into row Z, and then some, as the game drew to a conclusion. Not infamous for his finishing, but his defending was solid, and that's what he earns a wage for.